Pneumatic action for musical instruments.



L. B. DOMAN.

PNEUMATIC ACTION FOR MUSICAL INSTRUMENTS.

APPLICATION FILED JUNE 15, 1904.

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L. B. DOMAN.

PNEUMATIC ACTION FOR MUSICAL INSTRUMENTS.

APPLICATION FILED JUNE 15. 1904.

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Q/vdmeooeo V UM/Lm v #7 M A LEWIS BEN-l. DOMAN, OF ELBRIDGE, YORK.

PNEUMATIC ACTION FO R M'USIGAL INSTRUMENTS.

Specification of Letters Patent.

Patented July 6, 1909.

Application filed June 15, 1904. Serial No. 212,674.

To altwho m it may concern:

Be it known that I, Lnwrs B. DOMAN, a

citizen of the United States, residing at El-.

, ing is a specification.

- This invention relates to pneumatic actuating'means for musical instruments, especially pianos.

It is usual in mechanical laying attachments for pianos to emp y pneumatic means consisting of an exhausting means, as a bellows, actuated by the operator or by mechanical means as may be desired, and which acts pneumatically u on a series of neumatics or bellows each 0 which operates a key of the instrument. Various means have been proposed and are in use for regulating andcontrolling the pneumatic action.

It is the object of this invention to provide improvements in the control and regulation of.-the pneumatic action, and articularly in the tone-expression contro g devices, as will be hereinafter set-forth.

In the accompanying drawings, Figure 1 is a vertical transverse section of a mechanical piano pla er sufiicient to show an embodiment of t e invention; Fig. 2 is a vertical longitudinal section, broken away, of

improved means for exhausting the trackerboard passages and connections; Fig. 3 is an enlarged sectional view of a pneumatic and its' air chest; Fig. 4 is an enlarged sectional view of means for controlling the pneumatic action at will and Fig. 5 isa side View of a part of the apparatus shown in Fig. 1.

The apparatus comprises a frame A, in which are mounted wind-inducing devices or exhausting means which may consist of a. main bellows B and may be actuated by the operator or by other suitable means, an equalizer or receiver, as bellows C, whereby the pressure upon the various parts of the aparatus is equalized, and a pneumatic reguihtor D, for controlling the pressure and con-- necting the equalizer C with, sound producing devices or key pneumatics E each of which actuates one of the musical instrument keys or sound-producing devices F. The a paratus further comprises usual or suitab 0 means whereby a perforated sheet controls" the o eration of the individualumatics, an a partially exhausted chest through whichpass pipes connecting the municates wit tracker board with the individual pneumatics, whereby these pipes are cleared of air after operation. It further com rises a means K for controlling the connections between the equalizer C and a pneumatic L mounted on the pneumatic regulator D, whereby the pressure in the pneumatic regulator D, and therefore the force with which the ke s are struck, may be controlled prompt y by the operator.

A spring 1 secured to the bellows B and bearing against the frame A, tends to collapse the bellows, which bellows may be moved in the opposite direction by any suitable means, as a treadle, and is rovided with an outwardly-opening chec valve, (not shown). This is a well-known construction and needs no further description. The e ualizer C is in communication with the be ows by means of an opening 2. A spring 3 tends to distend the equalizer C and holds it from colla sing as it is exhausted by the bellows B. he equalizer C is in communication with. the pressure-controlling pneumatic D by an opening 4, and this pneu matic is connected by means of a conduit 5 with the chambers 7 of the air chests 6 of the individual Pneumatics. 1

The individual pneum'atics and-their air or wind chests are precisely alike, so that a description of one of them Will be sufiicient. Each wind chest consists of walls inclosing chambers 7 and 8, separated by a partition 9 in which is an opening 10 throu h which. the chambers may communicate. he chamber 8 communicates with the atmosphere by means of an openin 11 in which may be mounted the screw-ti for a purpose as will be hereinafter set forth. By means of a passage 13 the chamberS commat ics E. In the base of the chamber 7 is located a flexible diaphragm 14, on which is supported a valv'estem 15 guided by the gul e 16 fixed to'the chamber wall. At its 11 per end the valvestem supports a valve 17 W ich is looatedwithin the c iamber 8. This valve contains a recess upon its lower side for the rece tion of the valve stem, which recess is of'suflicient size to permit universal movement of the valve about the stem so that it may readily adjust itself to its seat. cess extends but a portion of the distance through the valve so that the point of suport lies between its upper and lower faces. Breferably the valve is leather-faced, and to readed brass sleeve 12- one of the individual pneu-- secure accurate seating of the valve, especially when the partition is of wood as is usually the case, the opening 10 in the partition between the chambers 7 and 8 is preferablyfitted with a metal eyelet 18. The eyelet also serves to bind the edge of the hole. The travel of the valve may be accurately adjusted by screwing the sleeve 12 up or down. Beneath the diaphragm is a recess 19 which communicates with a duct 20 in the trackerboard 21 by means of flexible tubes 22 and 23, which are connected by a metal section 24 secured in the chest H, which chest is artially exhausted through a duct 25 W ich connects it with the pressure-controlling pneumatic D. A small hole 26 in the metal section 24 permits the exhaust of the air remaining in the recess 19 and its connected pipes and passages after an operation has taken place.

The nfovable member of each of the individual pneumatics E is counectedby means of a rod 27 with a key hammer 28 pivoted at 29 in the frame A and having a felt striking face 30 adapted to strike one of the keys F. The rods 27 are secured to the hammers 28 and the bellows by means of suitable nuts 31.

The movable member 32 of the controlling pneumatic or pneumatic regulator D has a tendency to move outwardly under the influence of a spring 33 secured to the member 32 and to the frame A, while said member tends to move inwardly under atmospheric pres sure due tothe rarefication of the atmosphere within the pneumatic. A pin 34 fixed in the member 32 limits the collapse of the pneumatic. Upon theinterior of the member 32 is hinged a member 35 forming the movable member of the small pneumatic L mounted upon the interior of the pneumatic D. The member 35 carries a valve 136-adapted to control the lpressure in the pneumatic D by regulating t e flow through the passage 4 as it 1s moved toward and away from the mouth of that passage. The actuator pneumatic L is connected with the equalizer C by means of flexible ipes 36 and 37 and the controlling means The valve 136 is actuated by the actuator pneumatic L and also by the regulator pneumatic D.

The controlling means K comprises walls inclosing chambers 38 and 39, into which the pipes 36 and 37 respectively open. An opening 40 provides a means of communication between the chamber 38 and the atmosphere, but this opening is normally closed by a valve 41 constructed and mounted in a manner similar to the valves 17, and similarly the valve 41 is adapted to be seated in its lowest position upon a metal eyelet 42, located in an opening 43 between the chambers 38 and 39. The under side of a diaphra 44 is in communication with the atmos ere through an opening 45. As the cham er 39 is permanently in communication with the equalizer C, as shown, it is obvious that the diaphra m is normally forced upwardly and the va Va 41 seated against the opening 40, so that the chambers 38 and 39 are in communication with each other and are shut off from the atmosphere, vand therefore the interior of the pneumatic L and that of the equalizer C are connected together, and consequently the pneumatic L will be collapsed by the spring 60. The valve 41, however, 'may be moved downwardly to seat upon the metaleyelet-by means of a thumb-piece 46, when the pneumatic L will be shut off from communication with the equalizer C and will be placed in communication with the atmosphere. The pneumatic L will then be distended and the valve carried by it moved toward the open ing 4, and thereby restrict the flow therethrough.

The means G for actuating the perforated sheet 47 may consist of rollers 48 and 49 between which the sheet is passed over the end of the tracker-board, so as to shut oil the passages 20 from the atmosphere except when a perforation in the paper registers with a passage.

" The operation may be described as follows.

The parts being in the positions as-shown, when a perforation in the sheet 47 registers with a passage 20, the.atmospheric pressure 1 introduced below the diaphragm 14, there being a vacuum in the chamber 8, will cause the diaphragm to move upwardly andfthe valve 17 to cut off communication between the chamber Sand the atmosphere and place I that chamber in communication with'the chamber 7. The ap ropriate one of the individual pneumaticsli] having been thus connected with the exhaust ap aratus, that pneumatic will collapse, there y causing its 1 connected hammer 28 to strike one of the keys F. The perforation having passed andthe passageor duct 20 in question being again closed, the air in the chamber beneath the diaphragm 14 and in its connected pas- 1 sages will exhaust into the chamber H through the small hole 26. This hole should be of such size'that the air will not exhaust through it with sufficient rapidity to prevent the air entering the tracker-board from rais 1 ing the diaphragm 14 and the valve. sFor this reason the hole must necessarily be small and is liable to become clo ged with dust and dirt, but the location of t e pipe section in which it is formed being within the sepa- 1 rated chamber H having a lid 50, this hole ma be kept clear with small difficulty and wit out taking down a main air chest. The air having become exhausted in this manner from the chamber beneath the diaphragm, 1

the latter will dro to its lowest position and thus the pneumatic E will be cut of? from the exhaust a paratus and placed in communication wit the atmosphere, whereby it will be distended and thus placed in readiness for 1 member 32 of the pneumatic D will tend to move inwardly under atmospheric pressure against the tension of the spring-33. Suchmovement of the "member will cause, the valve 136 to approach the mouth of the opening 4, and it is obvious that the valve will maintain such a position with relation to that openin that an air tension will be maintained in the neumatic D and itsconnected passages whic will depend upon the strength of the spring 33. The pin 34'prevents the member 32 from moving inward ly sufficiently to completely close the opening 4. The parts being in the positions as indicated, the pneumatic L will be collapsed and the apparatus will be acting under full tension. The strongest stroke, and therefore the loudest sound, which is possible with the existing degree of exhaustion of the equalizer C will then e obtained. The rate of operation of the exhausting means, as the bellows B, may be changed and thereby crescendos and diminuendos produced at the will of the operator.

If, however, it is desired to produce a sudden change from loud to soft, this can be accom- V-p plished by-pressure upon thethumb piece 46,

which operates to place the interiorv of the small pneumatic L in communication with the atmosphere, while the connection with the equalizer O is cut OH. The introduction of the atmospheric pressure into the pneumatic L operates to distend that pneumatic, when the valve 136 will be moved toward the opening 4, thus controlling the air tension in the pneumatic D and roducing lighter blows upon the keys I. pon the release of the thumb piece 46 the pressure of the atmosphere will cause the valve 41 to move upwardly and close the o ening from the chamber 38 to the atmosp ere and at the same time connect that chamber with the equalizer C. This will resultin the rexhaustion of the small pneumatic L, when the member 35, and with it the valve, will be retracted against the member 32 by means of a spring (not shown).

While I have described .the controlling exhausting said pneumatics, a pneumatic connected to said key pneumatics and said exhausting means, a second pneumatic carried by the movable member of the aforesaid pneumatic, and means for alternately connectingsaid second pneumatic with said exhaustingmeans and with the atmosphere,

substantially as described.

2. In a pneumatic action for musical instruments, the combination with soundproducing or key pneumatics, of means for exhausting said pneumatics, a pneumatic connected. to said key pneumatics and said exhausting said pneumatics, a pneumatic connected to said key pneumatics and said exhausting means, a second pneumatic carriedby the movable member of the aforesaid neumatic, means for controlling the tension 1n said second pneumatic, and a valve controlling the connection between the first said pneumatic and said exhausting means and carried by themovable member of said second pneumatic, substantially as described.

4. In a pneumatic action for musical in struments, the combination with a trackerboard, of soundproducing or key pneumatics and air chests therefor, pipes connecting said tracker-board and air chests, a separate chest located between said tracker-board and air chests, through which said pipes pass, said pipes having'openings within said separate chest, and means for exhausting said separate chest, substantially as described.

5. In a'pneumatic action for musical instruments, the combination with a trackerboard, of sound-producing orkey pneumatics, of air chests therefor, pi es connecting said tracker-board and air-c ests, each of said pipes comprising flexible sections and a metal section, a separate chest located between said air-chests and said tracker-board, and inclosing said metal sections, said metal sections having holes opening within said separate chest, and means for exhausting said chest, substantially as described.

In testimony whereof I have signed my name to thisspecification in the presence of two subscribing witnesses.

LEWIS BEN-I. DOMAN.

Witnesses;

Mrs. THOMAS ELLIOTT, NETTIE A. BIBBINS. 

